Dexamethasone alone and in combination with desipramine, phenytoin, valproic acid or levetiracetam interferes with 5-ALA-mediated PpIX production and cellular retention in glioblastoma cells.

Extent of resection of glioblastoma (GBM) correlates with overall survival. Fluorescence-guided resection (FGR) using 5-aminolevulinic acid (5-ALA) can improve the extent of resection. Unfortunately not all patients given 5-ALA accumulate sufficient quantities of protoporphyrin IX (PpIX) for successful FGR. In this study, we investigated the effects of dexamethasone, desipramine, phenytoin, valproic acid, and levetiracetam on the production and accumulation of PpIX in U87MG cells. All of these drugs, except levetiracetam, reduce the total amount of PpIX produced by GBM cells (p < 0.05). When dexamethasone is mixed with another drug (desipramine, phenytoin, valproic acid or levetiracetam) the amount of PpIX produced is further decreased (p < 0.01). However, when cells are analyzed for PpIX cellular retention, dexamethasone accumulated significantly more PpIX than the vehicle control (p < 0.05). Cellular retention of PpIX was not different from controls in cells treated with dexamethasone plus desipramine, valproic acid or levetiracetam, but was significantly less for dexamethasone plus phenytoin (p < 0.01). These data suggest that medications given before and during surgery may interfere with PpIX accumulation in malignant cells. At this time, levetiracetam appears to be the best medication in its class (anticonvulsants) for patients undergoing 5-ALA-mediated FGR.

Rapid extraction-free detection of the R132H isocitrate dehydrogenase mutation in glioma using colorimetric peptide nucleic acid-loop mediated isothermal amplification (CPNA-LAMP).

The R132H isocitrate dehydrogenase one (IDH1) mutation is a prognostic biomarker present in a subset of gliomas and is associated with heightened survival when paired with aggressive surgical resection. In this study, we establish proof-of-principle for rapid colorimetric detection of the IDH1-R132H mutation in tumor samples in under 1 hour without the need for a nucleic acid extraction. Colorimetric peptide nucleic acid loop-mediated isothermal amplification (CPNA-LAMP) utilizes 4 conventional LAMP primers, a blocking PNA probe complementary to the wild-type sequence, and a self-annealing loop primer complementary to the single nucleotide variant to only amplify the DNA sequence containing the mutation. This assay was evaluated using IDH1-WT or IDH1-R132H mutant synthetic DNA, wild-type or IDH1-R132H mutant U87MG cell lysates, and tumor lysates from archived patient samples in which the IDH1 status was previously determined using immunohistochemistry (IHC). Reactions were performed using a hot water bath and visually interpreted as positive by a pink-to-yellow color change. Results were subsequently verified using agarose gel electrophoresis. CPNA-LAMP successfully detected the R132H single nucleotide variant, and results from tumor lysates yielded 100% concordance with IHC results, including instances when the single nucleotide variant was limited to a portion of the tumor. Importantly, when testing the tumor lysates, there were no false positive or false negative results.

Quantification of Protoporphyrin IX Accumulation in Glioblastoma Cells: A New Technique.

Introduction. 5-Aminolevulinic Acid (5-ALA) is a precursor of heme synthesis. A metabolite, protoporphyrin IX (PpIX), selectively accumulates in neoplastic tissue including glioblastoma. Presurgical administration of 5-ALA forms the basis of fluorescence-guided resection (FGR) of glioblastoma (GBM) tumors. However, not all gliomas accumulate sufficient quantities of PpIX to fluoresce, thus limiting the utility of FGR. We therefore developed an assay to determine cellular and pharmacological factors that impact PpIX fluorescence in GBM. This assay takes advantage of a GBM cell line engineered to express yellow fluorescent protein. Methods. The human GBM cell line U87MG was transfected with a YFP expression vector. After treatment with a series of 5-ALA doses, both PpIX and YFP fluorescence were measured. The ratio of PpIX to YFP fluorescence was calculated. Results. YFP fluorescence permitted the quantification of cell numbers and did not interfere with 5-ALA metabolism. The PpIX/YFP fluorescence ratio provided accurate relative PpIX levels, allowing for the assessment of PpIX accumulation in tissue. Conclusion. Constitutive YFP expression strongly correlates with cell number and permits PpIX quantification. Absolute PpIX fluorescence alone does not provide information regarding PpIX accumulation within the cells. Our research indicates that our PpIX/YFP ratio assay may be a promising model for in vitro 5-ALA testing and its interactions with other compounds during FGR surgery.

The antifibrotic drug halofuginone inhibits proliferation and collagen production by human leiomyoma and myometrial smooth muscle cells.

OBJECTIVE: To investigate the effects of the antifibrotic drug halofuginone on extracellular matrix production, cell proliferation, and apoptosis of cultured myometrial and leiomyoma smooth muscle cells. DESIGN: Comparative and controlled experimental research study. SETTING: University research laboratory. PATIENT(S): Leiomyoma and myometrial tissues were obtained from eight different patients at the time of elective hysterectomy. MAIN OUTCOME MEASURE(S): The effects of halofuginone on cell proliferation were assessed by tritiated thymidine uptake assays and cell count assays. Effects on TGFbeta1, collagen type I, and collagen type III mRNA levels were assessed by quantitative real-time polymerase chain reaction. Effects on apoptosis were assayed using a chemiluminescent assay to measure changes in caspase 3 and 7. RESULT(S): Halofuginone inhibited cell proliferation of both leiomyoma and autologous myometrial cells in a dose-dependent manner by inhibiting DNA synthesis within 24 hours and later inducing apoptosis (as measured by increased caspase 3/7) by 48-72 hours. Halofuginone also significantly reduced collagen type I (alpha1) and collagen type III (alpha1) mRNA levels, as well as the profibrotic factor TGFbeta1 mRNA levels in both cell types. CONCLUSION(S): These results provide evidence to support the use of the antifibrotic drug halofuginone as a novel drug treatment for uterine leiomyomas.

Basigin-mediated gene expression changes in mouse uterine stromal cells during implantation.

Implantation of mouse embryos is dependent on the proliferation and differentiation of uterine stromal cells in a process called decidualization. Decidualization both supports and limits the invasion of the implanting embryo and is regulated in part by the expression of matrix metalloproteinases (MMPs) and their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs). Molecules that alter the balance between MMP and TIMP expression could prevent implantation of the embryo. The membrane glycoprotein basigin (CD147/EMMPRIN), a known inducer of MMPs, is necessary for normal implantation in the mouse. The purpose of this study was to investigate the potential roles of basigin during implantation in the mouse. Using an in vitro stromal cell culture system, we found that recombinant human basigin protein (rBSG) increases MMP-3 and MMP-9 expression without altering TIMP-3 expression. Our results also showed rBSG induces expression of cytokines IL-1alpha/beta and leukocyte chemoattractants, CCL3, CCL20, CXCL2, and CXCL5. More importantly, rBSG significantly suppressed stromal cell decidualization as shown by the inhibition of alkaline phosphatase-2 expression and activity by rBSG. However, rBSG did not affect stromal cell proliferation. Taken together, our data indicate that basigin mediates gene expression changes in mouse uterine stromal cells and suggests that temporal and spatial regulation of basigin expression may be involved in the recruitment of leukocytes to the mouse uterus during early pregnancy.

Basigin-2 is a cell surface receptor for soluble basigin ligand.

The metastatic spread of a tumor is dependent upon the ability of the tumor to stimulate surrounding stromal cells to express enzymes required for tissue remodeling. The immunoglobulin superfamily protein basigin (EMMPRIN/CD147) is a cell surface glycoprotein expressed by tumor cells that stimulates matrix metalloproteinase and vascular endothelial growth factor expression in stromal cells. The ability of basigin to stimulate expression of molecules involved in tissue remodeling and angiogenesis makes basigin a potential target for the development of strategies to block metastasis. However, the identity of the cell surface receptor for basigin remains controversial. The goal of this study was to determine the identity of the receptor for basigin. Using a novel recombinant basigin protein (rBSG) corresponding to the extracellular domain of basigin, it was demonstrated that the native, nonglycosylated rBSG protein forms dimers in solution. Furthermore, rBSG binds to the surface of uterine fibroblasts, activates the ERK1/2 signaling pathway, and induces expression of matrix metalloproteinases 1, 2, and 3. Proteins that interact with rBSG were isolated using a biotin label transfer technique and sequenced by matrix-assisted laser desorption ionization tandem mass spectrophotometry. The results demonstrate that rBSG interacts with basigin expressed on the surface of fibroblasts and is subsequently internalized. During internalization, rBSG associates with a novel form of human basigin (basigin-3). It was concluded that cell surface basigin functions as a membrane receptor for soluble basigin and this homophilic interaction is not dependent upon glycosylation of the basigin ligand.

Expression of extracellular matrix metalloproteinase inducer and matrix metalloproteinases during mouse embryonic development.

Mouse embryo implantation is a highly invasive and controlled process that involves remodeling and degradation of the extracellular matrix of the uterus. Matrix metalloproteinases (MMPs) are the main proteinases facilitating this process. Extracellular matrix metalloproteinase inducer (EMMPRIN) can stimulate the production of MMPs and is required for successful implantation in the mouse. The aims of the present study were to examine the expression profiles of mRNA and proteins for EMMPRIN and MMPs in the developing mouse embryo in vitro, and to study whether EMMPRIN protein induces the production of MMPs by mouse blastocysts. EMMPRIN mRNA, detected by RT-PCR, was present at all stages of embryo development from the one-cell to the blastocyst outgrowth. EMMPRIN protein, observed by confocal microscopy, was present on the cell surface at the same stages of development as was the mRNA. Of seven MMPs studied, murine collagenase-like A (Mcol-A), murine collagenase-like B (Mcol-B) and gelatinase A (MMP-2) mRNAs were detected only in blastocyst outgrowths by RT-PCR. Gelatinase B (MMP-9) mRNA was detected both in expanded blastocysts and blastocyst outgrowths. MMP-2 and -9 proteins were detected in the cytoplasm of outgrowing trophoblast cells. Collagenase-2 (MMP-8), collagenase-3 (MMP-13), or stromelysin-1 (MMP-3) mRNAs were not present at any stage of pre- or peri-implantation mouse embryo development. Quantitative RT-PCR analyses showed that recombinant EMMPRIN protein did not stimulate MMP-2 or -9 expression by mouse blastocyst outgrowths. These data suggest that EMMPRIN may regulate physiological functions other than MMP production by mouse embryos during implantation.

A proteomic approach to identify phosphoproteins encoded by cDNA libraries.

We report a method for large-scale rapid analysis of phosphoproteins in tissues or cells by combining immobilized metal affinity chromatography (IMAC) with phage display cDNA library screening. We expressed a testis cDNA library as fusion proteins on phage and, using IMAC, enriched for sequences encoding phosphoproteins. Selected clones were polymerase chain reaction amplified and sequenced. The majority of the clones sequenced (80%) encoded known proteins previously identified as phosphoproteins. Immunoblotting with phosphotyrosine antibodies confirmed that some of the selected sequences encoded tyrosine phosphorylated proteins when expressed on phage. An advantage of this method is the rapid identification of phosphoproteins encoded by a cDNA library, which can identify proteins that are potentially phosphorylated in vivo. When this method is combined with limited enzymatic digestion and tandem mass spectrometric techniques, the specific phosphorylation site in a protein can be identified. This technique can be used in proteomics studies to effectively detect phosphorylated proteins and avoid time-consuming and expensive peptide sequencing.